Ammonium bromide composition



United States Patent 3,123,449 AMMONIUM BRGMEDE COMPGSKTKON Elmer L.McMaster and Floyd B. Nagle, both of Midland, Mich, assignors to The DowChemical Company, Midland, Mich, a corporation of Delaware No Drawing.Filed Nov. 17, 1961, Ser. No. 153,189 6 (Ilaims. (Cl. 23100) Thisinvention relates to ammonium bromide, and more particularly,'to acorrosion inhibiting ammonium bromide product and its method ofpreparation.

Ammonium bromide is corrosive to metals. This corrosiveness greatlylimits the utility of the material. The material is hydroscopic and alsosublimes at room temperature so that a metal in contact with the solidammonium bromide or an atmosphere exposed to ammonium bromide willcorrode extensively. Ammonium bromide has desirable properties in thatwhen it is dispersed in plastic material it imparts fire resistantproperties to the plastic. However, due to the corrosiveness of thematerial it is finding limited use for this purpose. It is difficult tostore and also corrodes the equipment used in molding or extruding theplastic material containing the ammonium bromide.

In addition to its corrosiveness ammonium bromide has anotherundesirable property which further limits its use as a fireproofingagent in plastics. Due to the hydroscopic properties of the ammoniumbromide and its sublimation, ammonium bromide upon storage tends to cakeor agglomerate and is difficult to disperse. To disperse the ammoniumbromide evenly in a plastic material, it is essential that the particlesof the ammonium bromide be of a small size, preferably less than 40microns. When larger particles are used or when the ammonium bromide isnot adequately dispersed, formation of specks or rough spots on thesurface of the fabricated plastic article is obtained. This adverselyaffects the appearance and saleability of the items. Thus, it isdesirable to have an ammonium bromide product which is inhibited todecrease its corrosiveness and also a method for the preparation of thisproduct in a fine particle size.

It is the principal object of this invention to provide an inhibitedcomposition of ammonium bromide to inhibit its corrosion of metals. Afurther object is to provide a free-flowing ammonium bromide product insmall particle size which will not cake or stick together upon storage.A still further object is to provide a method for the preparation of theinhibited ammonium product which is free-flowing and of small particlesize.

The above and other objects are attained according to the invention byintimately intermixing from 0.5 to

weight percent, based upon ammonium bromide, of a dialkylamine salt ofmonoor di-alkylphenyl ester of phosphoric acid. When the above compoundsare intermixed with ammonium bromide, the corrosiveness of the ammoniumbromide is inhibited. The solid particles of ammonium bromide in contactwith the metal will not corcode the metal nor will an aqueous solutionof the product be corrosive to the metal.

3,123,440 Patented Mar. 3, 1964 The compounds which are effective may berepresented by the following general formulae:

Where, in each of the above formulae, R R R and R represent an alkylradical having from 1 to 3 carbon atoms and R and R" are alkyl radicalshaving from 6 to 12 carbon atoms. The diethylamine salts of theoctylphenyl esters are preferred.

T he various known methods for intimately intermixing two materials maybe used in the formation of the in hibited ammonium bromide product.Generally, the most convenient methods of intermixing the additamentwith the solid ammonium bromide is to add the additament to the ammoniumbromide and then grind the mixture to obtain uniform distribution of theadditament throughout the ammonium bromide. Spray drying of ammoniumbromide solutions or emulsions containing the additament may be alsoused as a method to obtain the inhibited product.

Spray drying of ammonium bromide solutions or emulsions to which theadditaments have been added has a further advantage in that a fine,free-flowing product of ammonium bromide is obtained. The particlesobtained are in the range of a micron size and do not cake or adheretogether. Thus, spray drying provides a convenient method of not onlydispersing the inhibitor into the ammonium bromide, but the inhibitorserves an additional function of producing a fine free-flowing product.Spray drying of ammonium bromide solutions to obtain fine particles ofthe ammonium bromide without the addition of the additaments is notsatisfactory. The particles obtained by spray drying cake or adheretogether as soon as they are formed. Thus, large particles are obtainedor the particles adhere together making it diflicult to disperse them inplastic materials without the formation of specks or rough spots on thesurface of the material.

In preparing the stabilized ammonium bromide product by spray drying, anaqueous ammonium bromide solution to which the additament has been addedis used. Since the diethylamine salts of the octyl phenyl esters ofphosphoric acid are insoluble in water, an emulsion with the ammoniumbromide solution is prepared and then spray dried. In the preparation ofthese emulsions, it

may be desirable to use a surfactant or emulsifier, such as thepolyalkylene sorbitan esters of long chained acids as polyethylenesorbitan monolaurate, polyoxypropyleneethylene sorbitan monolaurate,polyethylene sorbitan tristearate, polyoxyethylene sorbitan pentaoleateor other well known emulsifiers. With the addition of an emulsisue-asapsame amount is also sufiicient to impart the free-flowing non-cakingcharacteristics to the particles when the ammonium bromide product isobtained by spray drying. It is preferred to use from 1 to 3 weightpercent of the additament.

The following example further illustrates the invention.

Example I An emulsion was made by intermixing 2 grams of a diethylaminesalt of a mixture of the monoand di-octylphenyl esters of phosphoricacid to 90 grams of a Weight percent ammonium bromide solution. A smallamount of a polyethylene sorbitan monolaurate as a dispersant was alsoadded. A mild steel coupon of /2" x 1" x A was inserted in the emulsion.A After 7 days the emulsion remained white and no discoloration of thesolution was obtained. The steel coupon was slightly dulled. A lossweight of about only 0.001 gram was obtained in the 7 days.

A second. run similar to the above was repeated except that only 0.37gram of the additament was added to the 90 grams of 20 weight percentammonium bromide solution. After 3 days the coupon was lustrous and thesolution or emulsion remained white and uncolored. A loss of 0.005 gramwas obtained.

A blank run was made where a similar mild steel coupon was placed in the20 weight percent solution. A loss of 0.04 gram was obtained and thesolution turned from white to an orange color in the three day test.

When an emulsion similar to that above is spray dried, the productobtained is white in color and free-flowing.

Similar results are obtained with dimethylarnine and dipropylamine saltsof the alkylphenyl esters having alkyl radicals of from 6 to 12 carbonatoms.

The application is a continuation-in-part of application Serial No.9,181, filed February 17, 1960, now Patent No. 3,037,842.

What is claimed is:

1. A free-flowing composition of matter which comprises ammonium bromideintimately intermixed with from 0.5 to 15 Weight percent, based on saidammonium bromide, of a compound selected from the group consisting ofthe dimethylamine salts, the diethylamine salts and the dipropylaminesalts of monoand di-alkylphenyl esters of phosphoric acid, said alkylgroups having from 6 to 12 carbon atoms.

2. A free-flowing composition of matter according to laim 1 wherein thediethylamine salt of dioctylphenyl ester of phosphoric acid isintermixed with the ammonium bromide in an amount of from 1 to 3 weightpercent, based on said ammonium bromide.

3. A free-flowing composition of matter according to claim 1 wherein thediethylamine salt of monooctylphenyl ester of phosphoric acid isintermixed with the ammonium bromide in an amount of from 1 to 3 weightpercent, based on said ammonium bromide.

4. In a process for the spray drying of ammonium bromide aqueoussolutions, the step to produce a freefiowing product of the ammoniumbromide, which comprises intermixing with the ammonium bromide aqueoussolution from 0.5 to 15 weight percent, based upon the ammonium bromide,of a compound selected from the group consisting of dirnethylaminesalts, diethylamine salts and dipropylamine salts of monoanddi-alkylphenyl esters of phosphoric acid, said alkyl groups having from6 to 12 carbon atoms.

5. A process according to claim 4 wherein diethylamine salt ofmonooctylphenyl ester of phosphoric acid is intermixed with the ammoniumbromide aqueous solution prior to spray drying in amount of from 1 to 3weight percent, based upon the ammonium bromide.

6. A process according to claim 4 wherein diethylamine salt ofdioctylphenyl ester of phosphoric acid is intermixed with the ammoniumbromide aqueous solution prior to spray drying in amount of from 1 to 3weight percent, based upon the ammonium bromide.

Referencestlited in the file of this patent UNITED STATES PATENTS2,403,762 Smith et al July 9, 1946 2,616,786 Whetstone Nov. 4, 19522,903,393 Allen et al Sept. 8, 1959

1. A FREE-FLOWING COMPOSITION OF MATTER WHICH COMPRISES AMMONIUM BROMIDEINTIMATELY INTERMIXED WITH FROM 0.5 TO 15 WEIGHT PERCENT, BASED ON SAIDAMMONIUM BROMIDE, OF A COMPOUND SELECTED FROM THE GROUP CONSISTING OFTHE DIMETHYLAMINE SALTS, THE DIETHYLAMINE SALTS AND THE DIPROPYLAMINESALTS OF MONO- AND DI-ALKYLPHENYL ESTERS OF PHOSPHORIC ACID, SAID ALKYLGROUPS HAVING FROM 6 TO 12 CARBON ATOMS.